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OVMAPI: 4.14.35-1902.x on ovm3: warning: cpu: 0 pid: 1115 at mm/usercopy.c:81 usercopy_warn+0x8e/0xa6 (Doc ID 2583767.1)

Last updated on FEBRUARY 26, 2020

Applies to:

Linux OS - Version Oracle Linux 7.5 with Unbreakable Enterprise Kernel [4.14.35] and later
Linux x86-64

Symptoms

Booting OL7 with UEK5/latest, i.e. 4.14.35-1902.* with OVMAPI enabled, produces a very visible notice to the user on console , and dmesg upon first boot

[ 16.417515] Bad or missing usercopy whitelist? Kernel memory exposure
attempt detected from SLUB object 'pool_workqueue' (offset 0, size 37)!
[ 16.418499] ------------[ cut here ]------------
[ 16.419023] WARNING: CPU: 0 PID: 851 at mm/usercopy.c:81
usercopy_warn+0x8e/0xa6
[ 16.419475] Modules linked in: ovmapi sunrpc xfs libcrc32c ext4 mbcache
jbd2 fscrypto coretemp crct10dif_pclmul crc32_pclmul ghash_clmulni_intel pcbc
xen_kbdfront xen_fbfront syscopyarea sysfillrect sysimgblt fb_sys_fops
aesni_intel crypto_simd glue_helper pcspkr cryptd binfmt_misc ip_tables btrfs
xor zstd_decompress zstd_compress xxhash raid6_pq xen_blkfront xen_netfront
crc32c_intel
[ 16.422005] CPU: 0 PID: 851 Comm: ovmd Not tainted
4.14.35-1902.3.2.el7uek.x86_64 #2
[ 16.422623] task: ffff8800b5ab5a00 task.stack: ffffc90001738000
[ 16.423151] RIP: e030:usercopy_warn+0x8e/0xa6
[ 16.423687] RSP: e02b:ffffc9000173bc80 EFLAGS: 00010246
[ 16.424216] RAX: 0000000000000081 RBX: ffffffff821e8c95 RCX:
0000000000000000
[ 16.424762] RDX: 0000000000000000 RSI: ffff8800bbc169c8 RDI:
ffff8800bbc169c8
[ 16.425309] RBP: ffffc9000173bca0 R08: ffffc9000173baf1 R09:
0000000000000149
[ 16.425859] R10: 000000000000495d R11: 0000000000aaaaaa R12:
0000000000000025
[ 16.426411] R13: ffff8800b628e125 R14: 0000000000000001 R15:
0000000000000025
[ 16.426983] FS: 00007f44281f0740(0000) GS:ffff8800bbc00000(0000)
knlGS:0000000000000000
[ 16.427550] CS: e033 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 16.428115] CR2: 00007fd0f529c000 CR3: 00000000ba6e6000 CR4:
0000000000002660
[ 16.428684] Call Trace:
[ 16.429251] __check_heap_object+0xb8/0x11b
[ 16.429826] __check_object_size+0xe3/0x1bc
[ 16.430377] ovmapi_ioctl+0x225/0xafa [ovmapi]
[ 16.430937] ? __raw_callee_save___native_queued_spin_unlock+0x15/0x0
[ 16.431511] ? __schedule+0x2c4/0x89b
[ 16.432099] ? do_wp_page+0x97/0x559
[ 16.432657] ? preempt_schedule_common+0x18/0x22
[ 16.433214] ? _cond_resched+0x1c/0x23
[ 16.433776] do_vfs_ioctl+0xaa/0x602
[ 16.434346] ? xen_hypercall_event_channel_op_compat+0xb/0x20
[ 16.434905] ? xen_hypercall_xen_version+0xa/0x20
[ 16.435465] SyS_ioctl+0x79/0x84
[ 16.436019] do_syscall_64+0x79/0x1b9
[ 16.436572] entry_SYSCALL_64_after_hwframe+0x169/0x0
[ 16.437132] RIP: 0033:0x7f44273f52f7
[ 16.437683] RSP: 002b:00007fff7a8f5238 EFLAGS: 00000246 ORIG_RAX:
0000000000000010
[ 16.438238] RAX: ffffffffffffffda RBX: 00007fff7a8f5290 RCX:
00007f44273f52f7
[ 16.438787] RDX: 00007fff7a8f5250 RSI: 0000000000000820 RDI:
0000000000000004
[ 16.439334] RBP: 0000000000eaf4a0 R08: 0000000000000100 R09:
0000000000000300
[ 16.439875] R10: 00007fff7a8f4e00 R11: 0000000000000246 R12:
0000000000ead6b0
[ 16.440403] R13: 0000000000000000 R14: 00007fff7a8f6f3a R15:
0000000000000000
[ 16.440919] Code: 1d 82 48 0f 45 f2 4c 89 44 24 10 48 89 c2 48 89 4c 24 08
48 89 1c 24 4d 89 d8 4c 89 d1 48 c7 c7 f8 8c 1e 82 31 c0 e8 95 e7 e7 ff <0f>
0b 48 83 c4 18 5b 5d c3 49 c7 c1 69 79 1f 82 4c 89 cb 4d 89
[ 16.442480] ---[ end trace 44a3480a3835773d ]---

Changes

UEK-5 kernel upgrade(in 4.14.35-1902.x series)

Cause

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In this Document
Symptoms
Changes
Cause
Solution
References

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